It's never going to happen. EVER.
First you'd have to get in touch with said celebrity, through their agent, who, if he or she ever got the request would immediately delete it.
If you ever got past that point (YOU NEVER WILL.) you'd have to pay them whatever "rate" they'd charge, and celebrities are logarithmically more expensive that amateur or professional tickle models.
YOU'D NEVER GET CLOSE TO BE ABLE TO AFFORD IT.
The only reason to do these videos is the hope that you make your money back/make a profit. With fewer people buying clips and the immediate pirating that goes on (and that clip would immediately
be pirated!) you'd make $20 if you were lucky, and would have lost about $300,000 or more, (probably much, much much more,) for hiring the celeb.
Then the celeb would never do it because the media is stupid, and salacious, and from that point on, they'd only ask about THAT tickle video. When the celeb would die, they know that would feature big in their
obituaries. I remember hearing that Liberace never admitted he was gay, even though everyone knew it, because he didn't want to be defined by it. Probably why Tarantino never admits to having a foot
fetish. I certainly don't blame them!
Jesus Christ in Heaven, can you imagine now, with the sewer that is Twitter and social media and the insane media we have? Ever suffer through an Entertainment Tonight interview from a shallow, dim witted host?
Then all the other little wannabe "famous" entertainment reporters? It'd be like throwing a perfectly cut prime steak to a starving lion.
So in conclusion, IT'S NEVER GOING TO HAPPEN, EVER.
That's why there's always fantasy....which plenty of talented people have written stories, done art work featuring celebrities or the characters they play having tickle fun.